Printing-press tympan



Ma ci. 1s 1924. 1,487,158 e. w. GOULD Filed Aug. 19, 1922 V Patented Mar. 18, 1924.

UNITED GEORGE W. GOULD, OF CHICAGO, ILLINOIS.

PRINTING-PRESS TYMPAN.

Application filed August 19 1922: Serial No. 582,870.

To all whom it may concern:

Be it known that I, Gnoncn W. GOULD, .a

citizen of the United States, and resident of Chicago, in the county of Cook and State of Illinois, have invented a certain new and.

useful Improvement in Printing Press Tympans, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying draw- 1 ings, forming a part of this specification.

In the usual rotary printing press the sheet of paper passes between an impression cylinder and a printing cylinder which prints upon one side of the sheet and then passes between a second impression cylinder and a second printing cylinder which prints upon the opposite side of the sheet. Unless some preventive means be provided the second impression cylinder will soon gather from'the first printed side of the sheet of paper sufficient ink seriously to impair the impression on the first printed side of the succeeding portion of the sheet. The means usually employed to prevent this impairment is a traveling tympan. The traveling tympan consists of a roll of chemically treated paper, often weighing as much as. fifteen hundred pounds or more, which passes over the second impression cylinder under the sheet of paper being printed upon and which travels through the press with the sheet of paper. This plan not only necessitates the use of a large roll of tympan paper and a complication of mechanism for passing the tympan paper through the press with a sheet of paper being printed upon,

but also the tympan paper is effective for such a limited number of impressions that the waste is great and the cost very execs sive: Another expedient is the so-called shifting tympan inwhich the tympan sheet, instead of traveling through the press, shifts on theimpression cylinder at very frequent intervals to present a fresh tympan surface. The same disadvantages which are inherent in thetraveling tympan are inherent in the shifting tympan.

The present invention providesa new tympan paper which need only be secured around the impression cylinder to form the peripheral surface of the latter, wholly eliminating the usual mechanism for passing a tympan through the ress or shifting it over the impression cy lnder, and entirely preventing impairment of the impression on the first printed side of the sheet of paper at an inconsequential cost. i

In the drawings,- I Figure 1 is a perspetive view, partly broken away, of a tympan sheet forming part of the invention.

Figure 2 is a sectional view, largely diagrammatic, of one form ofpressembodying the invention.

The tympan sheet A is a duplex or laminated sheet comprising a sheet 1 of material" possessing relatlvely great tensilestrength,

and a sheet 2 of material which is substantially oil and grease proof so that it will not absorb the oily ink from the first printed side of the sheet of paper being printed upon. Preferably the sheet 2 is a sheet of vegetable parchment paper; while the sheet 1 may be rope paper, kraft paper or other paper possessing considerable tensile strength. The sheets 1 and 2 are smoothly pasted together throughout their entire extent by a suitable paste-such as starch paste. Since the application'of'paste to the sheet 2 produces an immediate shrinkage and crinkling of the sheet while having little effect on the sheet 1, the two sheets are preferably pasted together to form the laminated sheet "by applying paste to one'or both of the sheets 1 and 2 and substantiallysimultaneously running them together between press rolls. I

In the usual press the sheet of paper being printed upon passes between the impression cylinder 5 and the printing cylinder 6 which prints upon one side of the sheet and then passes between the impression cylinder 7 and the printing cylinder 8 which prints upon the other side of the sheet. The side of the sheet printed upon' by the printing cylinder 6 must be protected against impairment as it passes over the impression cylinder 7. 'For'this purpose the surface ofthe impression cylinder 7 is covered with the duplex or laminated tympan sheet A which is secured thereon in any suitable manner.

The manner of securingthe duplex or laminated tympan sheet A around the impression cylinder 7 to form the eripheral surface thereof will vary in accordhnce with the construction of the various presses in use. The impression cylinder used in one form of press and the manner of securing the tympan sheet thereon is illustrated in the drawin s. In this type of press the impression cy inder 7 is composed of a plurality of segments 9 with slight spaces 10 between adjacent segments, each segment being separately covered with a tympan sheet A. For this purpose one end of the tympan'sheet A is formed with a tab 3, while the opposite end is bent downwardly to form a flange 4. A tympan sheet *A is laid upon a segment 9 with the flange 4, the inner surface of which is covered with paste or glue, contacting with the end wall of the segment 9. 'A pivoted bar 11 extends through the cylinder 7 and outside of one head of the cylinder the means of a nut and screw 13 bearing against the arm 12 the bar 11 may be operated to secure the flange ,4 of the tympan sheet A tightly against the end wall of the segment 9. The tab 3 of the tympan sheet is threaded through a slot of the shaft 14 which projects beyond one head of the cylinder 7' and which may be rotated by suitable means to draw the tympa n paper A tightly over the surface of the segment 9, the shaft being prevented from reversely rotating by the pawl and ratchet 15.

Whatever be the construction of the impression cylinder in a specific press the tympan sheet A will, by suitable means, be stretched tightly. around the impression cylinder to form the peripheral surface thereof. The strength necessary to enable the tympan sheet A to be stretched tightly over the impression cylinder and to stand usage during the operation of the press is imparted to the duplex or laminated sheet by the sheet 1 possessing considerable tensile strength. The exposed side of the duplex or laminated sheet which constitutes the surface of the impression cylinder conthrough the press the impression on the first printed side is entirely unimpaired during the printing of theimpression on the opposite side of the sheet.. Only a short length of the tympan sheet is required and it only has to be replaced after several hundred thousand impressions, so that the impairment of memes sheet of material possessing relatively great tensile strength and a sheet of vegetable parchment paper forming the exposed surface of the tympan. shaft of the bar 11 carries an arm 12. By

2. Atympan for printing presses, con

sisting of a laminated sheet made up of a sheet of material )ossessinrelativel reat D Y a tensile strength and a sheet of vegetable parchment paper forming the exposed surface of the tympan, the two sheets being smoothly and firmly pasted together throu hout their entire extent.

3. n a rotary printing press, the combination of an-impresion cylinder, and a tympan immovably secured to and forming the pe ripheral surface of the cylinder, the tympan consisting of a laminated sheet made up of a sheet of material possessing relatively great tensile strength and a sheet of vegetable parchment paper forming the exposed surface of the tympan.

41. In a rotary printing press, the combination of an impression cylinder, and a tympan immovably secured to and forming the peripheral surface of the cylinder, the tympan consisting of a laminated sheet made up of a sheet of material possessing relatively great tensile strength and a sheet of vegetable parchment paper forming the exposed surface of the tympan, the two sheets being smoothly and firmly pasted together throughout their entire extent.-

5. A tympanfor printing presses, comprising a sheet of material possessing rela tively great tensile strength, the exposed surface of the tympan being vegetable parchment paper. I

6. In a rotary printing press, the combination of an impression cylinder, and a tympan immovably secured to and forming the peripheral surface of'the cylinder, the tympan comprising a sheet of material possessing relatively great tensile strength, the exposed surface of the tympan being vegetable parchment paper.

In witness whereof, I hereunto subscribe my name this 17th day of August, 1922.

GEQRGE W; GOULD.

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